1. Field of the Invention
The present invention relates to a memory card, and more particularly, to an encryption processor of a memory card and a method of writing and reading data using the encryption processor.
2. Description of the Related Art
Memory cards are used in digital devices for writing and reading information. Examples of digital devices are digital cameras, personal digital assistants (PDAs), portable music players, mobile phones, personal computers, etc. A memory card typically includes two chips, such as a flash memory and a control chip. Flash memories, embedded for example in recent, conventional memory cards, have relatively high capacity storage capabilities.
A memory card typically stores data from a digital device in the flash memory unencrypted. However, a flash memory can be dumped by monitoring a bus between the control chip and the flash memory, and the data can be easily intercepted. Accordingly, a control chip may include an encryption processor to encrypt the data to be stored in the flash memory.
An encryption processor typically encrypts predetermined data first, and stores the encrypted data in a first-in-first-out (FIFO) memory in predetermined units. An error correcting code (ECC) value of the data stored in the FIFO memory is calculated and stored in the flash memory. Additionally, when decoding the encrypted data, a flash interface reads the encrypted data from the flash memory, and then stores the encrypted data in the FIFO memory. A central processing unit (CPU) reads the encrypted data from the FIFO memory and delivers the encrypted data to an internal memory, such as a random access memory (RAM), an electrically erasable programmable read only memory (EEPROM) or NOR flash memory. At this point, the encryption processor decodes the encrypted data stored in the internal memory, so that the desired data can be obtained. However, the encryption processor typically takes a relatively long time when encrypting or decoding the data. Also, the CPU may become overloaded.